The present invention relates generally to self-cleaning ovens, and more particularly, to a door latch mechanism and associated aspects thereof for self-cleaning ovens.
Ovens that are self-cleaning are well known. Such self-cleaning ovens include a cleaning mode or cycle that is initiated by a user. The self-cleaning cycle generates intense heat inside the oven. The intense heat reduces food particles, grease, spills and splatter (collectively, build-up) inside the oven to ash. Once the cleaning cycle is complete, the resulting ash may then be easily wiped away.
Because of the intense heat necessary to reduce such build-up to ash, self-cleaning ovens lock the oven door during the cleaning cycle to prevent access thereto. Self-cleaning ovens thus include a locking mechanism that keeps the oven door shut and locked during the cleaning cycle. While the locking mechanism may be manually actuated, most locking mechanisms in current self-cleaning ovens are automatically actuated when the self-cleaning mode is selected.
Such locking mechanisms include a latch that is controlled by the motor. The latch cooperates with a lock jamb in the door of the oven to lock the door when the door is in a closed position. The latch, via the motor, creates a compressive force between the door and the oven. This seals the oven door against the oven. Tolerance stack-up on doors, frames and hinges of the oven uses up the compressibility of the seal of the door and can cause current locking mechanisms to undesirably stall.
Current oven designs thus cause oven manufacturers to want a locking mechanism that has high strength and low cost. Strength or force has also begun to be associated with the position of the latch with respect to the door lock jamb. Higher strength or force for the locking mechanism translates into a higher cost. In order to lower the price for such locking mechanisms, force requirements have been eroded. Since over half the cost of such locking mechanisms is in the gear motor, reducing force requirements reduces the size of the motor necessary to achieve the required force by the latch. As an example, the following table (Table 1) illustrates how such force requirements have been eroded.
It is known art to drive or actuate the latch of the locking mechanism directly from the motor of the locking mechanism via lock levers. However, even with the reduction of force requirements and such direct drive mechanisms, the problem of stalling of the latch is still present.
In addition to providing a latching function, current locking mechanisms provide switches that control various aspects of the oven associated with or because of the self-cleaning mode. The switches in such current locking mechanisms are actuated via a radial (drum) cam that is driven by the motor. A radial or drum cam has a thickness or stack in proportion to the number of switches associated with the locking mechanism. A problem with such radial cams is that the thickness (height) of the drum stack would become too large to package the many switches that are now part of the locking mechanism in a convenient ganged array if the drum stack is too large, the locking mechanism becomes too thick for useful or practical packaging for ovens.
Therefore, each one of the many switches located on the locking mechanism requires two terminals (a set of terminals). Each set of terminals needs to be coupled to a controller or other component of the oven. Currently, each terminal of each set of terminals is connected to the controller or other component via an individual spade connector. During assembly, each spade connector must therefore be connected individually. This can present a problem of correctly connecting the various spade connectors.
What is therefore needed is a door locking mechanism for a self-cleaning oven that overcomes the disadvantages of the prior art. What is further needed is a door locking mechanism for a self-cleaning oven that is low cost, provides enough strength (force) for door closure retention, provides little or no stall, accommodates a plurality of switches, and is low-profile. What is therefore further needed is a door locking mechanism for a self-cleaning oven that can be retrofitted into existing self-cleaning oven models.
The present invention is a door latch mechanism and/or module for a self-cleaning oven. The door latch module is operative in one mode to securely latch or catch the oven door and in another mode to allow free movement of the oven door. The door latch module is adapted to be automatically driven. The door latch module includes and/or performs various features and/or functions.
According to an aspect of the subject invention, the door latch module includes reciprocating mechanical latching linkage that drives a latching hook. The latching hook cooperates with a latch catch in the oven door to retain the oven door in the one mode of operation. The mechanical latching linkage is configured as common pivot arms that provide a scissors action that reciprocates through a drive arm. The drive arm is coupled to a rotating member. Rotational movement of the rotating member is translated into near-linear, planar movement (latching movement) of the latching hook through the drive arm and the pivot arms.
In this manner, a class N (or other) motor may be used as a driver. Additionally, the latching linkage is configured to decrease latch speed at clamping or latching point. This increases the mechanical advantage at a clamping. As well, the likelihood of stalling is reduced. Further, the present latching linkage requires less torque to operate.
According to another aspect of the subject invention a door latch module includes a plurality of switches. The plurality of switches, in turn, have a corresponding plurality of terminals. The plurality of terminals for the door latch module are ganged or grouped to permit coupling with a single terminal interface. The single terminal interface may be configured to accept a modular plug. The modular plug may include releasable catches or the like.
According yet to another aspect of the subject invention, a door latch module includes a cam plate that is operative to selectively actuate and/or de-actuate select switches of the plurality of switches. The cam plate is driven by a driver (such as a motor) during the cleaning cycle or mode. The cam plate translates rotational motion of the motor to linear motion to actuate and/or de-actuate the switches.
In one form, the subject invention is a latch mechanism for a self-cleaning oven. The latch mechanism includes a support, a rotational member maintained by the support, and latch linkage maintained by the support. The latch linkage is coupled to the rotational member and has a hook operative to move into a first position and into a second position during rotation of the rotational member. The latch linkage includes a scissors mechanism coupling the rotational member with the hook.
In another form, the subject invention is a latch mechanism. The latch mechanism includes a rotating member and a drive arm having a first end connected to the rotating member and a second end. The latch mechanism further includes first and second coupling arms each having a first end connected to the second end of the drive arm at an interconnection, and an L-bracket having a first end rotatably mounted to a first fixed pivot point and having a second end for engaging a latch member. A second end of the first coupling arm is connected to the L-bracket and a second end of the second coupling arm is rotatably mounted to a second fixed pivot point. The interconnection is rotatable around a connecting member that floats in association with movement of the rotating member.